Apparently, reconfiguring drones is an idea whose time has come.
Earlier I noted an admirably simple folding quad copter, from a French team. This week I read of a group in Tokyo who see your quad copter and raise you four—a snaky octocopter that can configure in a zillion ways—the flying DRAGON  . So there!
This flying snake thing has modules connected by gimbals, each with two rotors, also on gimbals. Altogether, the assembly can bend in 6DOF, just like a robot arm. A flying robot arm.
“The researchers conceptualize this robot as a sort of overactuated flying arm that can both form new shapes and use those shapes to interact with the world around it by manipulating objects.” (from )
Reconfiguring in flight is, well, complicated.
A key feature of this design is that the rotors aren’t all in the same plane as in a rigid quadcopter. This is actually a key to stability: the rotors point in multiple directions and the body is rigid, yielding stable flight and hovering.
“To achieve an arbitrary 6DoF pose in the air, rotor disks cannot be aligned in the same plane, which is the case for traditional multirotors.” (, p. 1177)
The control system is modular, featuring “spinal” and “link” controllers, as well as a high level processor. Indeed, the device looks like nothing so much as a hovering spine.
The demo video shows an impressive maneuver, slinking thorough a small horizontal hole, unfurling while hovering and slipping link by link up through the floor. Pretty cool.
What’s more, the software autonomously determines the transformation needed. Very impressive.
This flying robot arm has the potential to be used as a flying robot arm: it can poke and grasp and carry cargo.
It will be interesting to see how this approach compares to swarms of rigid copters. What are the advantages and disadvantages of a handful of really complicated snakey fliers versus a constellation of many simpler fliers. (A swarm is probably harder to shoot down.)
I predict that this will soon be a moot question, because there will be swarms that can lock together into spines, and disperse again into drones, as needed.
- Evan Ackerman, Flying Dragon Robot Transforms Itself to Squeeze Through Gaps, in IEEE Spectrum – Robotics. 2018. https://spectrum.ieee.org/automaton/robotics/drones/flying-dragon-robot-transforms-itself-to-squeeze-through-gaps
- M. Zhao, T. Anzai, F. Shi, X. Chen, K. Okada, and M. Inaba, Design, Modeling, and Control of an Aerial Robot DRAGON: A Dual-Rotor-Embedded Multilink Robot With the Ability of Multi-Degree-of-Freedom Aerial Transformation. IEEE Robotics and Automation Letters, 3 (2):1176-1183, 2018. https://ieeexplore.ieee.org/document/8258850/